Once upon a time, there was the party of Lincoln. It was devoted to the idea of emancipation and 40 acres and a mule. Over the last 150 years, how times have changed. Today, in order to secure their electoral base, the Republican party has lowered itself to the lowest common denominator of its rabid base. It has become the Grand Old Party of racism.
Since the Southern strategy became the bread and butter of Republican electoral politics, a key shift happened in the party. As new (more Southern) elements gained power in the party, racism began rearing its ugly head from time to time. The most toxic of these outbreaks was the Louisiana politician, David Duke. A former Grand Wizard of the KKK, he ran semi-successful candidacies for the House (1989), the Senate (1990), governor of Louisiana (1991) and president (1992). While much of the national party repudiated Duke’s racism, his ability to collect votes in Louisiana pointed to a demographic and a fact just beneath the surface of the Republican Party. At the heart of the base (especially in Southern states) people with predominantly racist beliefs form the core of the party that Republicans rely on to get elected.
In recent years, the American electorate has basically broken itself down into thirds. About 25% of the electorate is liberal/progressive and about 35% of the electorate identifies as hard-core Republican/conservative. The remaining 40% or so occupy the mushy middle of non-ideologues, independents, libertarians, greens, and others. 40% might seem high, but that mushy middle has a tendency not to come out to vote. They are notoriously unpredictable. For much of the 1980s and 1990s, Republican electoral strategy was pretty simple. To win elections all you had to do was get out your base, and focus on enough single, hot-button social issues to swing key constituencies who might be found in that mushy middle. For example, you might go for the Catholic vote by focusing on abortion. Additionally, Republican strategists also tended to focus on negative advertising as a means of voter suppression. If middle-of-the-road voters were not breaking your candidate’s way, you could always swing enough mud to turn those voters (who were not very likely to vote anyway) off. Meanwhile, Democrats would have to both excite their base and manage to pull enough of those 40% to get a plurality.